<?php
// +----------------------------------------------------------------------
// | ThinkPHP [ WE CAN DO IT JUST THINK IT ]
// +----------------------------------------------------------------------
// | Copyright (c) 2006-2012 http://thinkphp.cn All rights reserved.
// +----------------------------------------------------------------------
// | Licensed ( http://www.apache.org/licenses/LICENSE-2.0 )
// +----------------------------------------------------------------------
// | Author: liu21st <liu21st@gmail.com>
// +----------------------------------------------------------------------

defined('THINK_PATH') or exit();
/**
 * Pgsql数据库驱动
 * @category   Extend
 * @package  Extend
 * @subpackage  Driver.Db
 * @author    liu21st <liu21st@gmail.com>
 */
class DbPgsql extends Db{

	/**
	 * 架构函数 读取数据库配置信息
	 * @access public
	 * @param array $config 数据库配置数组
	 */
	public function __construct($config='') {
		if ( !extension_loaded('pgsql') ) {
			throw_exception(L('_NOT_SUPPERT_').':pgsql');
		}
		if(!empty($config)) {
			$this->config   =   $config;
			if(empty($this->config['params'])) {
				$this->config['params'] =   array();
			}
		}
	}

	/**
	 * 连接数据库方法
	 * @access public
	 */
	public function connect($config='',$linkNum=0) {
		if ( !isset($this->linkID[$linkNum]) ) {
			if(empty($config))  $config =   $this->config;
			$pconnect   = !empty($config['params']['persist'])? $config['params']['persist']:$this->pconnect;
			$conn = $pconnect ? 'pg_pconnect':'pg_connect';
			$this->linkID[$linkNum] =  $conn('host='.$config['hostname'].' port='.$config['hostport'].' dbname='.$config['database'].' user='.$config['username'].'  password='.$config['password']);
			if (0 !== pg_connection_status($this->linkID[$linkNum])){
				throw_exception($this->error(false));
			}
			//设置编码
			pg_set_client_encoding($this->linkID[$linkNum], C('DB_CHARSET'));
			//$pgInfo = pg_version($this->linkID[$linkNum]);
			//$dbVersion = $pgInfo['server'];
			// 标记连接成功
			$this->connected    =   true;
			//注销数据库安全信息
			if(1 != C('DB_DEPLOY_TYPE')) unset($this->config);
		}
		return $this->linkID[$linkNum];
	}

	/**
	 * 释放查询结果
	 * @access public
	 */
	public function free() {
		pg_free_result($this->queryID);
		$this->queryID = null;
	}

	/**
	 * 执行查询 返回数据集
	 * @access public
	 * @param string $str  sql指令
	 * @return mixed
	 */
	public function query($str) {
		$this->initConnect(false);
		if ( !$this->_linkID ) return false;
		$this->queryStr = $str;
		//释放前次的查询结果
		if ( $this->queryID ) $this->free();
		N('db_query',1);
		// 记录开始执行时间
		G('queryStartTime');
		$this->queryID = pg_query($this->_linkID,$str);
		$this->debug();
		if ( false === $this->queryID ) {
			$this->error();
			return false;
		} else {
			$this->numRows = pg_num_rows($this->queryID);
			return $this->getAll();
		}
	}

	/**
	 * 执行语句
	 * @access public
	 * @param string $str  sql指令
	 * @return integer
	 */
	public function execute($str) {
		$this->initConnect(true);
		if ( !$this->_linkID ) return false;
		$this->queryStr = $str;
		//释放前次的查询结果
		if ( $this->queryID ) $this->free();
		N('db_write',1);
		// 记录开始执行时间
		G('queryStartTime');
		$result =   pg_query($this->_linkID,$str);
		$this->debug();
		if ( false === $result ) {
			$this->error();
			return false;
		} else {
			$this->numRows = pg_affected_rows($result);
			$this->lastInsID =   $this->last_insert_id();
			return $this->numRows;
		}
	}

	/**
	 * 用于获取最后插入的ID
	 * @access public
	 * @return integer
	 */
	public function last_insert_id() {
		$query  =   "SELECT LASTVAL() AS insert_id";
		$result =   pg_query($this->_linkID,$query);
		list($last_insert_id)   =   pg_fetch_array($result,null,PGSQL_ASSOC);
		pg_free_result($result);
		return $last_insert_id;
	}

	/**
	 * 启动事务
	 * @access public
	 * @return void
	 */
	public function startTrans() {
		$this->initConnect(true);
		if ( !$this->_linkID ) return false;
		//数据rollback 支持
		if ($this->transTimes == 0) {
			pg_exec($this->_linkID,'begin;');
		}
		$this->transTimes++;
		return ;
	}

	/**
	 * 用于非自动提交状态下面的查询提交
	 * @access public
	 * @return boolen
	 */
	public function commit() {
		if ($this->transTimes > 0) {
			$result = pg_exec($this->_linkID,'end;');
			if(!$result){
				$this->error();
				return false;
			}
			$this->transTimes = 0;
		}
		return true;
	}

	/**
	 * 事务回滚
	 * @access public
	 * @return boolen
	 */
	public function rollback() {
		if ($this->transTimes > 0) {
			$result = pg_exec($this->_linkID,'abort;');
			if(!$result){
				$this->error();
				return false;
			}
			$this->transTimes = 0;
		}
		return true;
	}

	/**
	 * 获得所有的查询数据
	 * @access private
	 * @return array
	 */
	private function getAll() {
		//返回数据集
		$result   =  pg_fetch_all($this->queryID);
		pg_result_seek($this->queryID,0);
		return $result;
	}

	/**
	 * 取得数据表的字段信息
	 * @access public
	 */
	public function getFields($tableName) {
		$result   =  $this->query("select a.attname as \"Field\",
            t.typname as \"Type\",
            a.attnotnull as \"Null\",
            i.indisprimary as \"Key\",
            d.adsrc as \"Default\"
            from pg_class c
            inner join pg_attribute a on a.attrelid = c.oid
            inner join pg_type t on a.atttypid = t.oid
            left join pg_attrdef d on a.attrelid=d.adrelid and d.adnum=a.attnum
            left join pg_index i on a.attnum=ANY(i.indkey) and c.oid = i.indrelid
            where (c.relname='{$tableName}' or c.relname = lower('{$tableName}'))   AND a.attnum > 0
                order by a.attnum asc;");
		$info   =   array();
		if($result) {
			foreach ($result as $key => $val) {
				$info[$val['Field']] = array(
                'name'    => $val['Field'],
                'type'    => $val['Type'],
                'notnull' => (bool) ($val['Null'] == 't'?1:0), // 't' is 'not null'
                'default' => $val['Default'],
                'primary' => (strtolower($val['Key']) == 't'),
                'autoinc' => (strtolower($val['Default']) == "nextval('{$tableName}_id_seq'::regclass)"),
				);
			}
		}
		return $info;
	}

	/**
	 * 取得数据库的表信息
	 * @access public
	 */
	public function getTables($dbName='') {
		$result = $this->query("select tablename as Tables_in_test from pg_tables where  schemaname ='public'");
		$info   =   array();
		foreach ($result as $key => $val) {
			$info[$key] = current($val);
		}
		return $info;
	}

	/**
	 * 关闭数据库
	 * @access public
	 */
	public function close() {
		if($this->_linkID){
			pg_close($this->_linkID);
		}
		$this->_linkID = null;
	}

	/**
	 * 数据库错误信息
	 * 并显示当前的SQL语句
	 * @access public
	 * @return string
	 */
	public function error($result = true) {
		$this->error = $result?pg_result_error($this->queryID): pg_last_error($this->_linkID);
		if('' != $this->queryStr){
			$this->error .= "\n [ SQL语句 ] : ".$this->queryStr;
		}
		trace($this->error,'','ERR');
		return $this->error;
	}

	/**
	 * SQL指令安全过滤
	 * @access public
	 * @param string $str  SQL指令
	 * @return string
	 */
	public function escapeString($str) {
		return pg_escape_string($str);
	}

	/**
	 * limit
	 * @access public
	 * @return string
	 */
	public function parseLimit($limit) {
		$limitStr    = '';
		if(!empty($limit)) {
			$limit  =   explode(',',$limit);
			if(count($limit)>1) {
				$limitStr .= ' LIMIT '.$limit[1].' OFFSET '.$limit[0].' ';
			}else{
				$limitStr .= ' LIMIT '.$limit[0].' ';
			}
		}
		return $limitStr;
	}
}